Having lived in the northeastern U.S. for some time before moving to Quebec, certainly some of the best things in these parts include colourful fall foliage and tons of locally-harvested maple syrup. Sadly, thanks to increasingly 'weird' and warming weather, the long-standing tradition and $65 million business of "maple sugaring" in the northeastern U.S. is in danger of becoming a historical footnote. Shorter and shorterIt's because the cycles of what is called 'cold recharge' — where weeks of below-freezing temperatures, followed by warmer temperatures — are shortening to the point where sugar maples are not producing the sap which is later boiled down to make maple syrup.

It this recharge cycle which allows the sap in sugar maples' limbs to turn to ice, creating an area of lower pressure which in turn pulls up more sap into the frozen areas from the roots up. In this state, the trees convert their stored starches into sucrose that will fuel spring budding. As the warming weather melts the sap ice, liquid sap is pushed in all directions. All one has to do is drill a hole for the sap to flow.

But for some places in the Northeast, the sugar-tapping season is either getting shorter and shorter, sometimes lasting only a week, as it did in Quebec last year.

"This is a weather-related industry," says Sam Cutting, owner of Dakin Farm in Vermont and who has been in the sugar business for 40 years. "There are always problems in the maple industry: gypsy moths, floods, droughts."

"Spiral of decline"Warmer weather has also translated to problems with pests such as the pear thrip, and the non-native Asian longhorn beetle destroying maple trees. Deer populations have also exploded in some places, meaning that more maple shoots are eaten before making it to maturity. It requires a mature tree of 40 to 50 years old to make maple syrup safely. Chemical pollutants from acid clouds are also a factor of stress.

"You have to look at the entire picture," says Timothy Perkins, director of the Proctor Maple Research Center at the University of Vermont. "Acid rain is always here now as a low-level stress. Then, when there's some sort of climactic disturbance or pest outbreak, the trees go into a spiral of decline."

Tree migrationFuture climate trends do not look like they will help the situation either. According to research from Barry Rock, professor of natural resources at the University of New Hampshire, the New England region has already warmed an average of 0.7Ëš F over the last hundred years, with the bulk of that warming in the winter — an average gain of 1.8Ëš F.

Migration of tree species is nothing new, and occurred as a natural response to gradual changes in climate in the past. But in this case, it seems to be accelerating at an unprecedented rate. According to research by UVM ecologist Brian Beckage, tree species have shifted more than 90 meters up the slopes of the Green Mountains since 1964, following the movement of cooler climates.

What it means is that the migration and disappearance of the sugar maple out of the Northeast U.S. may be ultimately inevitable.

"I'm a Vermonter and when I think of New England I think of certain things: maple syrup, colorful fall foliage," says Professor Rock. "But with 6Ëš to 10Ëš warming we won't have maples."